1. Field of the Invention
The present invention relates to a device and method for correcting mask pattern which can correct flare generated in lithographic process, one of a process step in fabrication of semiconductor devices, and also to a device and method for correcting light exposure.
2. Description of the Related Art
Recent pattern formation of semiconductor devices adopts projection exposure apparatuses based on dioptric system or cata-dioptric system. In this sort of projection exposure apparatus, light ascribable to some optical routes not intended on the design basis, tends to generate due to reflection and scattering on the surface or inside of lenses in the lighting optical system, photomask, projection lens and so forth, or due to non-uniformity in refractive index of lens materials. The light is generally referred to as “flare”, and is causative of variation in a pattern to be transferred or in line width.
FIG. 25 is a drawing schematically showing a mode of flare generation.
In a unit shot region 121 for a single time of light exposure, a transferred pattern formed by light exposure through a mask pattern on a photomask is irradiated also by flare of the exposure light, which has come through arbitrary regions B, C away from point A. It is known that distance over which the flare can affect reaches as long as several millimeters on the basis of distance transferred on a wafer, a target object for the pattern transfer. A flare affective to as far as several millimeters is referred to as “long-range flare”, a flare of several micrometer affective to as far as several tens of micrometers is referred to as “midrange flare”, and a flare affective to as far as several micrometers or less is referred to as “short-range” flare.
In recent years, as typically described in Patent Document 1, there is proposed a technique by which the midrange and short-range flares (local flares) are estimated by using a test pattern composed of a line pattern and an annular pattern surrounding thereof, and width of the transferred pattern is corrected based on the estimation.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2004-126486
The above-described conventional technique could certainly estimate the local flares, which have never been even noticed as a problem to a reasonable degree, with a high accuracy, but it has been found that the method was suffering from difference in the correction accuracy locally in a single shot region, and could not be said as having reached a satisfactory accuracy yet. This applies not only the midrange and short-range flares, but also to the long-range flare, and this creates the present situation in need of development of a dimensional correction technique with a higher accuracy.
The present invention is conceived after considering the above-described subjects, and an objects thereof is to provide a device and method for correcting a mask pattern, and a device and method for correcting light exposure, all of which make it possible to estimate and correct flare with an extremely high accuracy, over the entire portion not only of a single shot region, but also of a single chip region, to thereby realize a lithographic process causative of only an extremely small dimensional variation in line width, and further to thereby realize highly-reliable semiconductor devices.